Grant: Operating Grant: ECI grants in Maternal, Reproductive, Child & Youth Health

Infertility affects 15% of couples world-wide, and male factors contribute to half of cases. The most severe form of male infertility, termed non-obstructive azoospermia (NOA) occurs where no sperm are produced due to defective spermatogenesis. An overwhelming 70% of these cases have no known cause. Treatment options are limited and involve a surgical procedure termed microTESE where a surgical microscope is used to identify dilated seminiferous tubules in the testis that are most likely to contain a degree of preserved sperm production, compared to the vast majority of collapsed tubules lacking sperm production. This technique is the last option for fertility and is only successful in approximately half of cases; thus, research is desperately needed to understand the mechanisms underlying these severely infertile men with NOA to progress care This study will investigate the mechanisms that distinguish active and defective spermatogenesis with the aim to identify novel therapeutic targets. To do this, we will compare testis tissue from men with NOA and control men with normal sperm production. We will use state-of-the-art single cell sequencing which allows us to study the precise genetic expression within each individual cell from each testis biopsy. Using advanced analysis techniques, we will identify differences in cell-type-specific gene isoforms and expression between normal controls and men with NOA including comparisons between dilated tubules (with spermatogenesis) and collapsed tubules (defect spermatogenesis). Using specialized 3-D organoid cultures, we will investigate the regulatory differences in germ cell and somatic cell interactions among the experimental groups. Results from this study will contribute to our understanding of the mechanisms and identification of novel therapeutic targets among severely infertile men with no presently available treatment.